RANK and RANKL Expression in Tumors of Patients with Early Breast Cancer.

Area of Science:

• Oncology
• Molecular Biology
• Cancer Research

Background:

• The receptor activator of nuclear factor-κB (RANK) pathway is implicated in breast cancer pathogenesis.
• Previous studies on the prognostic value of the RANK/RANKL pathway in breast cancer have yielded inconsistent results.

Purpose of the Study:

• To investigate the prognostic significance of RANK and RANKL protein expression in early breast cancer.
• To correlate RANK and RANKL expression with disease-free survival (DFS) and overall survival (OS).

Main Methods:

• Analysis of RANK and RANKL protein expression in 607 early breast cancer patient samples using immunohistochemical staining on tissue microarrays.
• Quantification of expression via H-scores with defined cut-off values for RANK (≥8.5) and RANKL (≥0).

Main Results:

• No significant correlation was found between RANK and RANKL expression (ρ = -0.04).
• Higher RANK expression was observed in triple-negative and HER2-positive breast tumors, but RANKL expression showed no subtype specificity.
• While higher RANKL expression showed a trend towards better prognosis, neither RANK nor RANKL expression reached statistical significance as prognostic factors for DFS or OS.

Conclusions:

• Tumor-specific RANK and RANKL expression are not applicable as prognostic factors for disease-free survival and overall survival in early breast cancer.
• RANK and RANKL expression may be associated with subtype-specific breast cancer progression.